Apparatus and methods to communicatively couple field devices to controllers in a process control system

ABSTRACT

Example apparatus and methods to communicatively couple field devices to controllers in a process control system are disclosed. A disclosed example apparatus includes a first interface configured to receive first information from a field device using a first communication protocol. The example apparatus also includes a communication processor communicatively coupled to the first interface and configured to encode the first information for communication via a bus using a second communication protocol. In addition, the example apparatus includes a second interface communicatively coupled to the communication processor and the bus and configured to communicate the first information via the bus using the second communication protocol. The bus is configured to use the second communication protocol to communicate second information associated with another field device.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to process control systems and,more particularly, to apparatus and methods to communicatively couplefield devices to controllers in a process control system.

BACKGROUND

Process control systems, like those used in chemical, petroleum,pharmaceutical, pulp and paper, or other manufacturing processes,typically include one or more process controllers communicativelycoupled to at least one host including at least one operator workstationand to one or more field devices configured to communicate via analog,digital or combined analog/digital communication protocols. The fielddevices, which may be, for example, device controllers, valves, valveactuators, valve positioners, switches and transmitters (e.g.,temperature, pressure, flow rate, and chemical composition sensors) orcombinations thereof, perform functions within the process controlsystem such as opening or closing valves and measuring or inferringprocess parameters. A process controller receives signals indicative ofprocess measurements made by the field devices and/or other informationpertaining to the field devices, uses this information to implement acontrol routine, and generates control signals that are sent over thebuses or other communication lines to the field devices to control theoperation of the process control system.

A process control system can include a plurality of field devices thatprovide several different functional capabilities and that are oftencommunicatively coupled to process controllers using two-wire interfacesin a point-to-point (e.g., one field device communicatively coupled to afield device bus) or a multi-drop (e.g., a plurality of field devicecommunicatively coupled to a field device bus) wiring connectionarrangements or with wireless communications. Some field devices areconfigured to operate using relatively simple commands and/orcommunications (e.g., an ON command and an OFF command). Other fielddevices are more complex requiring more commands and/or morecommunication information, which may or may not include simple commands.For example, more complex field devices may communicate analog valueswith digital communications superimposed on the analog value using, forexample, a Highway Addressable Remote Transducer (“HART”) communicationprotocol. Other field devices can use entirely digital communications(e.g., a FOUNDATION Fieldbus communication protocol).

In a process control system, each field device is typically coupled to aprocess controller via one or more I/O cards and a respectivecommunication medium (e.g., a two-wire cable, a wireless link, or anoptical fiber). Thus, a plurality of communication media are required tocommunicatively couple a plurality of field devices to a processcontroller. Often the plurality of communication media coupled to thefield devices are routed through one or more field junction boxes, atwhich point, the plurality of communication media are coupled torespective communication media (e.g., respective two-wire conductors) ofa multi-conductor cable used to communicatively couple the field devicesto the process controller via one or more I/O cards.

SUMMARY

Example apparatus and methods to communicatively couple field devices tocontrollers in a process control system are described. In accordancewith an example, an example apparatus includes a first interfaceconfigured to receive first information from a field device using afirst communication protocol. The example apparatus also includes acommunication processor communicatively coupled to the first interfaceand configured to encode the first information for communication via abus using a second communication protocol. In addition, the exampleapparatus includes a second interface communicatively coupled to thecommunication processor and the bus and configured to communicate thefirst information via the bus using the second communication protocol.The bus is configured to use the second communication protocol tocommunicate second information associated with another field device.

In accordance with another example, an example method involves receivingfirst information from a field device using a first communicationprotocol. The first information is then encoded for communication usinga second communication protocol configured to communicate secondinformation associated with another field device. The first informationis then communicated to a controller via a bus using the secondcommunication protocol.

In accordance with yet another example, an example apparatus includes aplurality of sockets configured to receive a plurality of terminationmodules. Each of the termination modules is configured to becommunicatively coupled to at least one field device in a processcontrol system. The example apparatus also includes a communication businterface communicatively coupled to each of the plurality of socketsand configured to communicate first field device information associatedwith one of the termination modules and second field device informationassociated with a second one of the termination modules.

In accordance with a further example, an example apparatus includes aconnection detector configured to detect a connection to a field device.The example apparatus also includes a field device identifier configuredto determine field device identification information indicative of theidentity of the field device. In addition, the example apparatusincludes a display interface configured to display the field deviceidentification information.

In accordance with yet a further example, an example apparatus includesa first isolation circuit communicatively coupled to termination modulecircuitry and configured to be communicatively coupled to a bus. Thetermination module circuitry is configured to communicate with a fielddevice and the bus enables the termination module to communicate with acontroller. The example apparatus also includes a second isolationcircuit communicatively coupled to the termination module circuitry andconfigured to be communicatively coupled to a power supply that provideselectrical power to the termination module circuitry.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an example process controlsystem.

FIGS. 1B-1D depict alternative example implementations that may be usedto communicatively couple workstations, controllers, and I/O cards.

FIG. 2 is a detailed diagram of the example marshalling cabinet of FIG.1A.

FIG. 3 is another example marshalling cabinet that may be used toimplement the example marshalling cabinet of FIG. 1A.

FIG. 4 depicts a top view and FIG. 5 depicts a side view of an exampletermination module of FIGS. 1A and 2.

FIG. 6 is a detailed block diagram of the example termination module ofFIGS. 1A, 2, 4, and 5.

FIG. 7 is a detailed block diagram of an example I/O card of FIG. 1A.

FIG. 8 is a detailed block diagram of an example labeler that may beused to display field device identification information and/or any otherfield device information in association with the termination modules ofFIGS. 1A and 2-6.

FIG. 9 depicts an isolation circuit configuration that may beimplemented in connection with the example termination modules of FIG.1A to electrically isolate the termination modules from one another,from field devices, and from communication buses.

FIGS. 10A and 10B depict a flowchart of an example method that may beused to implement the termination modules of FIGS. 1A and 2-6 tocommunicate information between field devices and I/O cards.

FIGS. 11A and 11B depict a flowchart of an example method that may beused to implement the I/O cards of FIG. 1A to communicate informationbetween the termination modules and a workstation.

FIG. 12 is a flowchart of an example method that may be used toimplement the labeler of FIGS. 2, 3, 6, and 8 to retrieve and displayinformation associated with field devices communicatively coupled totermination modules.

FIG. 13 is a block diagram of an example processor system that may beused to implement the example systems and methods described herein.

DETAILED DESCRIPTION

Although the following describes example apparatus and systemsincluding, among other components, software and/or firmware executed onhardware, it should be noted that such systems are merely illustrativeand should not be considered as limiting. For example, it iscontemplated that any or all of these hardware, software, and firmwarecomponents could be embodied exclusively in hardware, exclusively insoftware, or in any combination of hardware and software. Accordingly,while the following describes example apparatus and systems, persons ofordinary skill in the art will readily appreciate that the examplesprovided are not the only way to implement such apparatus and systems.

An example process control system includes a control room (e.g., acontrol room 108 of FIG. 1A), a process controller area (e.g. a processcontroller area 110 of FIG. 1A), a termination area (e.g., a terminationarea 140 of FIG. 1A), and one or more process areas (e.g., process areas114 and 118 of FIG. 1A). A process area includes a plurality of fielddevices that perform operations (e.g., controlling valves, controllingmotors, controlling boilers, monitoring, measuring parameters, etc.)associated with performing a particular process (e.g., a chemicalprocess, a petroleum process, a pharmaceutical process, a pulp and paperprocess, etc.). Some process areas are not accessible by humans due toharsh environment conditions (e.g., relatively high temperatures,airborne toxins, unsafe radiation levels, etc.) The control roomtypically includes one or more workstations within an environment thatis safely accessible by humans. The workstations include userapplications that users (e.g., engineers, operators, etc.) can access tocontrol operations of the process control system by, for example,changing variable values, process control functions, etc. The processcontrol area includes one or more controllers communicatively coupled tothe workstation(s) in the control room. The controllers automate controlof the field devices in the process area by executing process controlstrategies implemented via the workstation. An example process strategyinvolves measuring a pressure using a pressure sensor field device andautomatically sending a command to a valve positioner to open or close aflow valve based on the pressure measurement. The termination areaincludes a marshalling cabinet that enables the controllers tocommunicate with the field devices in the process area. In particular,the marshalling cabinet includes a plurality of termination modules usedto marshal, organize, or route signals from the field devices to one ormore I/O cards communicatively coupled to the controllers. The I/O cardstranslate information received from the field devices to a formatcompatible with the controllers and translate information from thecontrollers to a format compatible with the field devices.

Known techniques used to communicatively couple field devices within aprocess control system to controllers involve using a separate bus(e.g., a wire, a cable, or a circuit) between each field device and arespective I/O card communicatively coupled to a controller (e.g., aprocess controller, a programmable logic controller, etc.). An I/O cardenables communicatively coupling a controller to a plurality of fielddevices associated with different data types or signal types (e.g.,analog in (AI) data types, analog out (AO) data types, discrete in (DI)data types, discrete out (DO) data types, digital in data types, anddigital out data types)) and different field device communicationprotocols by translating or converting information communicated betweenthe controller and the field devices. For example, an I/O card may beprovided with one or more field device interfaces configured to exchangeinformation with a field device using the field device communicationprotocol associated with that field device. Different field deviceinterfaces communicate via different channel types (e.g., analog in (AI)channel types, analog out (AO) channel types, discrete in (DI) channeltypes, discrete out (DO) channel types, digital in channel types, anddigital out channel types)). In addition, the I/O card can convertinformation (e.g., voltage levels) received from the field device intoinformation (e.g., pressure measurement values) that the controller canuse to perform operations associated with controlling the field device.The known techniques require a bundle of wires or buses (e.g., amulti-core cable) to communicatively couple a plurality of field devicesto I/O cards. Unlike known techniques that use a separate bus tocommunicatively couple each field device to I/O cards, the exampleapparatus and methods described herein may be used to communicativelycouple field devices to an I/O card by terminating a plurality of fielddevices at a termination panel (e.g., a marshalling cabinet) and usingone bus (e.g., a conductive communication medium, an opticalcommunication medium, a wireless communication medium) communicativelycoupled between the termination panel and the I/O card tocommunicatively couple the field devices to the I/O card.

The example apparatus and methods described herein involve using anexample universal I/O bus (e.g., a common or shared communication bus)that communicatively couples one or more termination modules to one ormore I/O cards communicatively coupled to a controller. Each terminationmodule is communicatively coupled to one or more respective fielddevices using a respective field device bus (e.g., an analog bus or adigital bus). The termination modules are configured to receive fielddevice information from the field devices via the field device buses andcommunicate the field device information to the I/O cards via theuniversal I/O bus by, for example, packetizing the field deviceinformation and communicating the packetized information to the I/Ocards via the universal I/O bus. The field device information mayinclude, for example, field device identification information (e.g.,device tags, electronic serial numbers, etc.), field device statusinformation (e.g., communication status, diagnostic health information(open loop, short, etc.)), field device activity information (e.g.,process variable (PV) values), field device description information(e.g., field device type or function such as, for example, valveactuator, temperature sensor, pressure sensor, flow sensor, etc.), fielddevice connection configuration information (e.g., multi-drop busconnection, point-to-point connection, etc.), field device bus orsegment identification information (e.g., field device bus or fielddevice segment via which field device is communicatively coupled totermination module), and/or field device data type information (e.g., adata type descriptor indicative of the data type used by a particularfield device). The I/O card(s) can extract the field device informationreceived via the universal I/O bus and communicate the field deviceinformation to the controller, which can then communicate some or all ofthe information to one or more workstation terminals for subsequentanalysis.

To communicate field device information (e.g., commands, instructions,queries, threshold activity values (e.g., threshold PV values), etc.)from workstation terminals to field devices, I/O cards can packetize thefield device information and communicate the packetized field deviceinformation to a plurality of termination modules. Each of thetermination modules can then extract or depacketize respective fielddevice information from the packetized communications received from arespective I/O card and communicate the field device information to arespective field device.

In the illustrated examples described herein, a termination panel (e.g.,a marshalling cabinet) is configured to receive (e.g., connect to) aplurality of termination modules, each of which is communicativelycoupled to a different field device. To indicate at the terminationpanel which termination modules are connected to which field devices,each termination module is provided with a termination labeler (ortagging system). A termination labeler includes an electronic display(e.g., a liquid crystal display (LCD)) and components to determine whichfield device or devices is/are connected to the termination modulecorresponding to the termination labeler. In some exampleimplementations, displays are mounted on the termination panel insteadof the termination modules. Each of the displays is mounted inassociation with a respective termination module socket. In this manner,when a termination module is removed from the termination panel, acorresponding display remains on the termination panel for use by asubsequently connected termination module.

Now turning to FIG. 1A, an example process control system 100 includes aworkstation 102 communicatively coupled to a controller 104 via a bus orlocal area network (LAN) 106, which is commonly referred to as anapplication control network (ACN). The LAN 106 may be implemented usingany desired communication medium and protocol. For example, the LAN 106may be based on a hardwired or wireless Ethernet communication protocol.However, any other suitable wired or wireless communication medium andprotocol could be used. The workstation 102 may be configured to performoperations associated with one or more information technologyapplications, user-interactive applications, and/or communicationapplications. For example, the workstation 102 may be configured toperform operations associated with process control-related applicationsand communication applications that enable the workstation 102 and thecontroller 104 to communicate with other devices or systems using anydesired communication media (e.g., wireless, hardwired, etc.) andprotocols (e.g., HTTP, SOAP, etc.). The controller 104 may be configuredto perform one or more process control routines or functions that havebeen generated by a system engineer or other system operator using, forexample, the workstation 102 or any other workstation and which havebeen downloaded to and instantiated in the controller 104. In theillustrated example, the workstation 102 is located in a control room108 and the controller 104 is located in a process controller area 110separate from the control room 108.

In the illustrated example, the example process control system 100includes field devices 112 a-c in a first process area 114 and fielddevices 116 a-c in a second process control area 118. To communicateinformation between the controller 104 and the field devices 112 a-c and116 a-c, the example process control system 100 is provided with fieldjunction boxes (FJB's) 120 a-b and a marshalling cabinet 122. Each ofthe field junction boxes 120 a-b routes signals from respective ones ofthe field devices 112 a-c and 116 a-c to the marshalling cabinet 122.The marshalling cabinet 122, in turn, marshals (e.g., organizes, groups,etc) information received from field devices 112 a-c and 116 a-c androutes the field device information to respective I/O cards (e.g., I/Ocards 132 a-b and 134 a-b) of the controller 104. In the illustratedexample, the communications between the controller 104 and the fielddevices 112 a-c and 116 a-c are bidirectional so that the marshallingcabinet 122 is also used to route information received from I/O cards ofthe controller 104 to respective ones of the field devices 112 a-c and116 a-c via the field junction boxes 120 a-b.

In the illustrated example, the field devices 112 a-c arecommunicatively coupled to the field junction box 120 a and the fielddevices 116 a-c are communicatively coupled to the field junction box120 b via electrically conductive, wireless, and/or opticalcommunication media. For example, the field junction boxes 120 a-b maybe provided with one or more electrical, wireless, and/or optical datatransceivers to communicate with electrical, wireless, and/or opticaltransceivers of the field devices 112 a-c and 116 a-c. In theillustrated example, the field junction box 120 b is communicativelycoupled wirelessly to the field device 116 c. In an alternative exampleimplementation, the marshalling cabinet 122 may be omitted and signalsfrom the field devices 112 a-c and 116 a-c can be routed from the fieldjunction boxes 120 a-b directly to the I/O cards of the controller 104.In yet another example implementation, the field junction boxes 120 a-bmay be omitted and the field devices 112 a-c and 116 a-c can be directlyconnected to the marshalling cabinet 122.

The field devices 112 a-c and 116 a-c may be Fieldbus compliant valves,actuators, sensors, etc., in which case the field devices 112 a-c and116 a-c communicate via a digital data bus using the well-known Fieldbuscommunication protocol. Of course, other types of field devices andcommunication protocols could be used instead. For example, the fielddevices 112 a-c and 116 a-c could instead be Profibus, HART, or AS-icompliant devices that communicate via the data bus using the well-knownProfibus and HART communication protocols. In some exampleimplementations, the field devices 112 a-c and 116 a-c can communicateinformation using analog communications or discrete communicationsinstead of digital communications. In addition, the communicationprotocols can be used to communicate information associated withdifferent data types.

Each of the field devices 112 a-c and 116 a-c is configured to storefield device identification information. The field device identificationinformation may be a physical device tag (PDT) value, a device tag name,an electronic serial number, etc. that uniquely identifies each of thefield devices 112 a-c and 116 a-c. In the illustrated example of FIG.1A, the field devices 112 a-c store field device identificationinformation in the form of physical device tag values PDT0-PDT2 and thefield devices 116 a-c store field device identification information inthe form of physical device tag values PDT3-PDT5. The field deviceidentification information may be stored or programmed in the fielddevices 112 a-c and 116 a-c by a field device manufacturer and/or by anoperator or engineer involved in installation of the field devices 112a-c and 116 a-c.

To route information associated with the field devices 112 a-c and 116a-c in the marshalling cabinet 122, the marshalling cabinet 122 isprovided with a plurality of termination modules 124 a-c and 126 a-c.The termination modules 124 a-c are configured to marshal informationassociated with the field devices 112 a-c in the first process area 114and the termination modules 126 a-c are configured to marshalinformation associated with the field devices 116 a-c in the secondprocess area 118. As shown, the termination modules 124 a-c and 126 a-care communicatively coupled to the field junction boxes 120 a-b viarespective multi-conductor cables 128 a and 128 b (e.g., a multi-buscable). In an alternative example implementation in which themarshalling cabinet 122 is omitted, the termination modules 124 a-c and126 a-c can be installed in respective ones of the field junction boxes120 a-b.

The illustrated example of FIG. 1A depicts a point-to-pointconfiguration in which each conductor or conductor pair (e.g., bus,twisted pair communication medium, two-wire communication medium, etc.)in the multi-conductor cables 128 a-b communicates information uniquelyassociated with a respective one of the field devices 112 a-c and 116a-c. For example, the multi-conductor cable 128 a includes a firstconductor 130 a, a second conductor 130 b, and a third conductor 130 c.Specifically, the first conductor 130 a is used to form a first data busconfigured to communicate information between the termination module 124a and the field device 112 a, the second conductor 130 b is used to forma second data bus configured to communicate information between thetermination module 124 b and the field device 112 b, and the thirdconductor 130 c is used to form a third data bus configured tocommunicate information between the termination module 124 c and thefield device 112 c. In an alternative example implementation using amulti-drop wiring configuration, each of the termination modules 124 a-cand 126 a-c can be communicatively coupled with one or more fielddevices. For example, in a multi-drop configuration, the terminationmodule 124 a can be communicatively coupled to the field device 112 aand to another field device (not shown) via the first conductor 130 a.In some example implementations, a termination module can be configuredto communicate wirelessly with a plurality of field devices using awireless mesh network.

Each of the termination modules 124 a-c and 126 a-c may be configured tocommunicate with a respective one of the field devices 112 a-c and 116a-c using a different data type. For example, the termination module 124a may include a digital field device interface to communicate with thefield device 112 a using digital data while the termination module 124 bmay include an analog field device interface to communicate with thefield device 112 b using analog data.

To control I/O communications between the controller 104 (and/or theworkstation 102) and the field devices 112 a-c and 116 a-c, thecontroller 104 is provided with the plurality of I/O cards 132 a-b and134 a-b. In the illustrated example, the I/O cards 132 a-b areconfigured to control I/O communications between the controller 104(and/or the workstation 102) and the field devices 112 a-c in the firstprocess area 114, and the I/O cards 134 a-b are configured to controlI/O communications between the controller 104 (and/or the workstation102) and the field devices 116 a-c in the second process area 118.

In the illustrated example of FIG. 1A, the I/O cards 132 a-b and 134 a-breside in the controller 104. To communicate information from the fielddevices 112 a-c and 116 a-c to the workstation 102, the I/O cards, 132a-b and 134 a-b communicate the information to the controller 104 andthe controller 104 communicates the information to the workstation 102.Similarly, to communicate information from the workstation 102 to thefield devices 112 a-c and 116 a-c, the workstation 102 communicates theinformation to the controller 104, the controller 104 then communicatesthe information to the I/O cards 132 a-b and 134 a-b, and the I/O cards132 a-b and 134 a-b communicate the information to the field devices 112a-c and 116 a-c via the termination modules 124 a-c and 126 a-c. In analternative example implementation, the I/O cards 132 a-b and 134 a-bcan be communicatively coupled to the LAN 106 internal to the controller104 so that the I/O cards 132 a-b and 134 a-b can communicate directlywith the workstation 102 and/or the controller 104.

To provide fault tolerant operations in the event that either of the I/Ocards 132 a and 134 a fails, the I/O cards 132 b and 134 b areconfigured as redundant I/O cards. That is, if the I/O card 132 a fails,the redundant I/O card 132 b assumes control and performs the sameoperations as the I/O card 132 a would otherwise perform. Similarly, theredundant I/O card 134 b assumes control when the I/O card 134 a fails.

To enable communications between the termination modules 124 a-c and theI/O cards 132 a-b and between the termination modules 126 a-c and theI/O cards 134 a-b, the termination modules 124 a-c are communicativelycoupled to the I/O cards 132 a-b via a first universal I/O bus 136 a andthe termination modules 126 a-c are communicatively coupled to the I/Ocards 134 a-b via a second universal I/O bus 136 b. Unlike themulti-conductor cables 128 a and 128 b, which use separate conductors orcommunication mediums for each one of the field devices 112 a-c and 116a-c, each of the universal I/O buses 136 a-b is configured tocommunicate information corresponding to a plurality of field devices(e.g., the field devices 112 a-c and 116 a-c) using the samecommunication medium. For example, the communication medium may be aserial bus, a two-wire communication medium (e.g., twisted-pair), anoptical fiber, a parallel bus, etc. via which information associatedwith two or more field devices can be communicated using, for example,packet-based communication techniques, multiplexing communicationtechniques, etc.

In an example implementation, the universal I/O buses 136 a-b areimplemented using the RS-485 serial communication standard. The RS-485serial communication standard can be configured to use lesscommunication control overhead (e.g., less header information) thanother known communication standards (e.g., Ethernet). However, in otherexample implementations, the universal I/O buses 136 a-b can beimplemented using any other suitable communication standard includingEthernet, universal serial bus (USB), IEEE 1394, etc. In addition,although the universal I/O buses 136 a-b are described above as wiredcommunication mediums, in another example implementation, one or both ofthe universal I/O buses 136 a-b can be implemented using a wirelesscommunication medium (e.g., wireless Ethernet, IEEE-802.11, Wi-Fi®,Bluetooth®, etc.).

The universal I/O buses 136 a and 136 b are used to communicateinformation in substantially the same manner. In the illustratedexample, the I/O bus 136 a is configured to communicate informationbetween the I/O cards 132 a-b and the termination modules 124 a-c. TheI/O cards 132 a-b and the termination modules 124 a-c use an addressingscheme to enable the I/O cards 132 a-b to identify which informationcorresponds to which one of the termination modules 124 a-c and toenable each of the termination modules 124 a-c to determine whichinformation corresponds to which of the field devices 112 a-c. When atermination module (e.g., one of the termination modules 124 a-c and 126a-c) is connected to one of the I/O cards 132 a-b and 134 a-b, that I/Ocard automatically obtains an address of the termination module (from,for example, the termination module) to exchange information with thetermination module. In this manner, the termination modules 124 a-c and126 a-c can be communicatively coupled anywhere on the respective buses136 a-b without having to manual supply termination module addresses tothe I/O cards 132 a-b and 134 a-b and without having to individuallywire each of the termination modules 124 a-c and 126 a-c to the I/Ocards 132 a-b and 134 a-b.

By using the universal I/O buses 136 a-b, the number of communicationmedia (e.g., wires) required to communicate information between themarshalling cabinet 122 and the controller 104 is substantially reducedrelative to known configurations that require a separate communicationmedium for each termination module to communicate with a controller.Reducing the number of communication media (e.g., reducing the number ofcommunication buses or communication wires) required to communicativelycouple the marshalling cabinet 122 to the controller 104 reducesengineering costs required to design and generate drawings forinstallation of the connections between the controller 104 and the fielddevices 112 a-c and 116 a-c. In addition, reducing the number ofcommunication media, in turn, reduces installation costs and maintenancecosts. For example, one of the I/O buses 136 a-b replaces a plurality ofcommunication media used in known systems to communicatively couplefield devices to a controller. Therefore, instead of maintaining aplurality of communication media for communicatively coupling the fielddevices 112 a-c and 116 a-c to the I/O cards 132 a-b and 134 a-b, theillustrated example of FIG. 1A requires substantially less maintenanceby using the I/O buses 136 a-b.

In addition, reducing the number of communication media required tocommunicatively couple the marshalling cabinet 122 to the I/O cards 132a-b and 134 a-b results in more available space for more terminationmodules (e.g., the termination modules 124 a-b and 124 a-c), therebyincreasing the I/O density of the marshalling cabinet 122 relative toknown systems. In the illustrated example of FIG. 1A, the marshallingcabinet 122 can hold a number of termination modules that wouldotherwise require more marshalling cabinets (e.g., three marshallingcabinets) in a known system implementation.

By providing the termination modules 124 a-c and the termination modules126 a-c that can be configured to use different data type interfaces(e.g., different channel types) to communicate with the field devices112 a-c and 116 a-c and that are configured to use respective common I/Obuses 136 a and 136 b to communicate with the I/O cards 132 a-b and 134a-b, the illustrated example of FIG. 1A enables routing data associatedwith different field device data types (e.g., the data types or channeltypes used by the field devices 112 a-c and 116 a-c) to the I/O cards132 a-b and 134 a-b without having to implement a plurality of differentfield device interface types on the I/O cards 132 a-b and 134 a-b.Therefore, an I/O card having one interface type (e.g., an I/O businterface type for communicating via the I/O bus 136 a and/or the I/Obus 136 b) can communicate with a plurality of field devices havingdifferent field device interface types.

Using the I/O bus 136 a and/or the I/O bus 136 b to exchange informationbetween the controller 104 and the termination modules 124 a-c and 126a-c enables defining field device-to-I/O card connection routing late ina design or installation process. For example, the termination modules124 a-c and 126 a-c can be placed in various locations within themarshalling cabinet 122 while maintaining access to a respective one ofthe I/O buses 136 a and 136 b.

In the illustrated example, the marshalling cabinet 122, the terminationmodules 124 a-c and 126 a-c, the I/O cards 132 a-b and 134 a-b, and thecontroller 104 facilitate migrating existing process control systeminstallations to a configuration substantially similar to theconfiguration of the example process control system 100 of FIG. 1A. Forexample, because the termination modules 124 a-c and 126 a-c can beconfigured to include any suitable field device interface type, thetermination modules 124 a-c and 126 a-c can be configured to becommunicatively coupled to existing field devices already installed in aprocess control system. Similarly, the controller 104 can be configuredto include a known LAN interface to communicate via a LAN to an alreadyinstalled workstation. In some example implementations, the I/O cards132 a-b and 134 a-b can be installed in or communicatively coupled toknown controllers so that controllers already installed in a processcontrol system need not be replaced.

In the illustrated example, the I/O card 132 a includes a data structure133 and the I/O card 134 a includes a data structure 135. The datastructure 133 stores the field device identification numbers (e.g.,field device identification information) corresponding to field devices(e.g., the field devices 112 a-c) that are assigned to communicate withthe I/O card 132 a via the universal I/O bus 136 a. The terminationmodules 124 a-c can use the field device identification numbers storedin the data structure 133 to determine whether a field device isincorrectly connected to one of the termination modules 124 a-c. Thedata structure 135 stores the field device identification numbers (e.g.,field device identification information) corresponding to field devices(e.g., the field devices 116 a-c) that are assigned to communicate withthe I/O card 134 a via the universal I/O bus 136 b. The data structures133 and 135 can be populated by engineers, operators, and/or users viathe workstation 102 during a configuration time or during operation ofthe example process control system 100. Although not shown, theredundant I/O card 132 b stores a data structure identical to the datastructure 133 and the redundant I/O card 134 b stores a data structureidentical to the data structure 135. Additionally or alternatively, thedata structures 133 and 135 can be stored in the workstation 102.

In the illustrated example, the marshalling cabinet 122 is shown locatedin a termination area 140 separate from the process control area 110. Byusing the I/O buses 136 a-b instead of substantially more communicationmedia (e.g., a plurality of communication buses, each uniquelyassociated with one of the field devices 112 a-c and 116 a-c) tocommunicatively couple the termination modules 124 a-c and 126 a-c tothe controller 104 facilitates locating the controller 104 relativelyfarther from the marshalling cabinet 122 than in known configurationswithout substantially decreasing the reliability of communications. Insome example implementations, the process control area 110 and thetermination area 140 can be combined so that the marshalling cabinet 122and the controller 104 are located in the same area. In any case,placing the marshalling cabinet 122 and the controller 104 in areasseparate from the process areas 114 and 118 enables isolating the I/Ocards 132 a-b and 134 a-b, the termination modules 124 a-c and 126 a-cand the universal I/O buses 136 a-b from harsh environmental conditions(e.g., heat, humidity, electromagnetic noise, etc.) that may beassociated with the process areas 114 and 118. In this manner, the costand complexity of designing and manufacturing the termination modules124 a-c and 126 a-c and the I/O cards 132 a-b and 134 a-b can besubstantially reduced relative to the cost of manufacturingcommunications and control circuitry for the field devices 112 a-c and116 a-c because the termination modules 124 a-c and 126 a-c and the I/Ocards 132 a-b and 134 a-b do not require operating specificationfeatures (e.g., shielding, more robust circuitry, more complex errorchecking, etc.) required to guarantee reliable operation (e.g., reliabledata communications) as would otherwise be necessary to operate in theenvironmental conditions of the process areas 114 and 118.

FIGS. 1B-1D depict alternative example implementations that may be usedto communicatively couple workstations, controllers, and I/O cards. Forexample, in the illustrated example depicted in FIG. 1B a controller 152(which performs substantially the same functions as the controller 104of FIG. 1A) is communicatively coupled to I/O cards 154 a-b and 156 a-bvia a backplane communication bus 158. The I/O cards 154 a-b and 156 a-bperform substantially the same functionality as the I/O cards 132 a-band 134 a-b of FIG. 1A and are configured to be communicatively coupledto the universal I/O buses 136 a-b to exchange information with thetermination modules 124 a-c and 126 a-c. To communicate with theworkstation 102, the controller 152 is communicatively coupled to theworkstation 102 via the LAN 106.

In another illustrated example depicted in FIG. 1C a controller 162(which performs substantially the same functions as the controller 104of FIG. 1A) is communicatively coupled to the workstation 102 and aplurality of I/O cards 164 a-b and 166 a-b via the LAN 106. The I/Ocards 164 a-b and 166 a-b perform substantially the same functionalityas the I/O cards 132 a-b and 134 a-b of FIG. 1A and are configured to becommunicatively coupled to the universal I/O buses 136 a-b to exchangeinformation with the termination modules 124 a-c and 126 a-c. However,unlike the I/O cards 132 a-b and 134 a-b of FIG. 1A and the I/O cards154 a-b and 156 a-b of FIG. 1B, the I/O cards 164 a-b and 166 a-b areconfigured to communicate with the controller 162 and the workstation102 via the LAN 102. In this manner, the I/O cards 164 a-b and 166 a-bcan exchange information directly with the workstation 102.

In yet another illustrated example depicted in FIG. 1D, I/O cards 174a-b and 176 a-b (which perform substantially the same functions as theI/O cards 132 a-b and 134 a-b of FIG. 1A) are implemented in aworkstation 172 (which performs substantially the same functions as theworkstation 102 of FIG. 1A). In some example implementations, thephysical I/O cards 174 a-b and 176 a-b are not included in theworkstation 172, but the functionality of the I/O cards 174 a-b and 176a-b are implemented in the workstation 172. In the illustrated exampleof FIG. 1D, the I/O cards 174 a-b and 176 a-b are configured to becommunicatively coupled to the universal I/O buses 136 a-b to exchangeinformation with the termination modules 124 a-c and 126 a-c. Also, inthe illustrated example of FIG. 1D, the workstation 172 may beconfigured to perform substantially the same functions as the controller104 so that a controller need not be provided to perform a processcontrol strategy. However, a controller may be provided.

FIG. 2 is a detailed diagram of the example marshalling cabinet 122 ofFIG. 1A. In the illustrated example, the marshalling cabinet 122 isprovided with socket rails 202 a and 202 b to receive the terminationmodules 124 a-c. In addition, the marshalling cabinet 122 is providedwith an I/O bus transceiver 206 that communicatively couples thetermination modules 124 a-c to the universal I/O bus 136 a describedabove in connection with FIG. 1A. The I/O bus transceiver 206 may beimplemented using a transmitter amplifier and a receiver amplifier thatconditions signals exchanged between the termination modules 124 a-c andthe I/O cards 132 a-b. The marshalling cabinet 122 is provided withanother universal I/O bus 208 communicatively coupling the terminalmodules 124 a-c to the I/O bus transceiver 206. In the illustratedexample, the I/O bus transceiver 206 is configured to communicateinformation using a wired communication medium. Although not shown, themarshalling cabinet 122 may be provided with another I/O bus transceiversubstantially similar or identical to the I/O bus transceiver 206 tocommunicatively couple the termination modules 126 a-c with the I/Ocards 134 a-b.

Using a common communication interface (e.g., the I/O bus 208 and theI/O bus 136 a) to exchange information between the I/O cards 132 a-b andthe termination modules 124 a-c enables defining field device-to-I/Ocard connection routing late in a design or installation process. Forexample, the termination modules 124 a-c can be communicatively coupledto the I/O bus 208 at various locations (e.g., various terminationmodule sockets of the socket rails 202 a-b) within the marshallingcabinet 122. In addition, the common communication interface (e.g., theI/O bus 208 and the I/O bus 136 a) between the I/O cards 132 a-b and thetermination modules 124 a-c reduces the number of communication media(e.g., the number of communication buses and/or wires) between the I/Ocards 132 a-b and the termination modules 124 a-c, thus enablinginstallation of relatively more of the termination modules 124 a-c(and/or the termination modules 126 a-c) in the marshalling cabinet 122than the number of known termination modules that can be installed inknown marshalling cabinet configurations.

To display field device identification information and/or other fielddevice information in association with the termination modules 124 a-c,each of the termination modules 124 a-c is provided with a display 212(e.g., an electronic termination label). The display 212 of thetermination module 124 a displays the field device identification (e.g.,a field device tag) of the field device 112 a (FIG. 1A). In addition,the display 212 of the termination module 124 a can be used to displayfield device activity information (e.g., measurement information, linevoltages, etc.), data type information (e.g., analog signal, digitalsignal, etc.), field device status information (e.g., device on, deviceoff, device error, etc.), and/or any other field device information. Ifthe termination module 124 a is configured to be communicatively coupledto a plurality of field devices (e.g., the field device 112 a of FIG. 1Aand other field devices (not shown)), the display 212 can be used todisplay field device information associated with all of the fielddevices communicatively coupled to the termination module 124. In theillustrated example, the displays 212 are implemented using liquidcrystal displays (LCD's). However, in other example implementations, thedisplays 212 can be implemented using any other suitable displaytechnology.

To retrieve the field device identification information and/or otherfield device information, each of the termination modules 124 a-c isprovided with a labeler 214 (e.g., a termination labeler). For example,when the field device 112 a is communicatively coupled to thetermination module 124 a, the labeler 214 of the termination module 124a retrieves the field device identification information and/or any otherfield device information from the field device 112 a (and/or other fielddevices communicatively coupled to the termination module 124 a) anddisplays the information via the display 212 of the termination module124 a. The labelers 214 are described in detail below in connection withFIG. 8. Providing the display 212 and the labeler 214 decreases thecosts and installation time associated with manually attaching labels towires and/or buses associated with termination modules and fielddevices. However, in some example implementations, manual wire labelingmay also be used in connection with the display 212 and labeler 214. Forexample, the field devices 112 a-c and 116 a-c may be communicativelycoupled to the I/O cards 132 a-b and 134 a-b relatively quickly by usingthe display 212 and the labeler 214 to determine which of the fielddevices 112 a-c and 116 a-c is connected to each of the terminationmodules 124 a-c and 126 a-c. Subsequently, after installation iscomplete, labels may optionally be added to the buses or wires extendingbetween the termination modules 124 a-c and 126 a-c and the fielddevices 112 a-c and 114 a-c. The display 212 and the labeler 214 canalso decrease costs and time associated with maintenance operations byconfiguring the display 212 and the labeler 214 to display statusinformation (e.g., device error, device alarm, device on, device off,device disabled, etc.) to facilitate a trouble shooting processes.

To provide electrical power to the termination modules 124 a-c, the I/Obus transceiver 206, and the displays 212, the marshalling cabinet 122is provided with a power supply 216. In the illustrated example, thetermination modules 124 a-c use the electrical power from the powersupply 216 to power communication channels or communication interfacesused to communicate with field devices (e.g., the field devices 112 a-cof FIG. 1A) and/or to provide the field devices electrical power foroperation.

FIG. 3 is another example marshalling cabinet 300 that may be used toimplement the example marshalling cabinet 122 of FIG. 1A. In theillustrated example, the marshalling cabinet 300 is provided with awireless I/O bus communication controller 302 to communicate with thecontroller 104 of FIG. 1A wirelessly via a wireless universal I/Oconnection 304. As shown in FIG. 3, a plurality of termination modules306 substantially similar or identical to the termination modules 124a-c and 126 a-c of FIG. 1A are plugged into rail sockets 308 a and 308 band communicatively coupled to the wireless I/O bus communicationcontroller 302 via a universal I/O bus 309 internal to the marshallingcabinet 300. In the illustrated example, the wireless I/O buscommunication controller 302 emulates an I/O card (e.g., the I/O card134 a of FIG. 1A) of the controller 104 of FIG. 1A to enable thetermination modules 306 to communicate with the controller 104.

Unlike the illustrated example of FIG. 2 in which the displays 212 aremounted on the termination modules 124 a-c, in the illustrated exampleof FIG. 3, a plurality of displays 310 are mounted in the marshallingcabinet 300 in association with sockets to receive termination modules.In this manner, when one of the termination modules 306 is plugged inand communicatively coupled to a field device (e.g., one of the fielddevices 112 a-c and 116 a-c of FIG. 1A), a labeler 214 of thetermination module 306 and a respective one of the displays 310 can beused to display the field device identification information indicativeof the field device connected to the termination module 306. Thedisplays 310 can also be used to display any other field deviceinformation. The marshalling cabinet 300 is provided with a power supply312 that is substantially similar or identical to the power supply 216of FIG. 2.

FIG. 4 depicts a top view and FIG. 5 depicts a side view of the exampletermination module 124 a of FIGS. 1A and 2. In the illustrated exampleof FIG. 4, the display 212 is on a top surface of the exampletermination module 124 a so that the display 212 is visible to anoperator or user during operation when the termination module 124 a isplugged into the rail socket 202 a (FIG. 3). As shown in the illustratedexample of FIG. 5, the example termination module 124 a is removablycoupled to a base 402. The example termination module 124 a includes aplurality of contacts 404 (two of which are shown) that communicativelycouple and/or electrically couple the termination module 124 a to thebase 402. In this manner, the base 402 can be coupled to the marshallingcabinet 122 (FIGS. 1A and 2), and the termination module 124 a can becoupled to and removed from the marshalling cabinet 122 via the base402. The base 402 is provided with termination screws 406 (e.g., a fielddevice interface) to tie down or secure conductive communication media(e.g., a bus) from the field device 112 a. When the termination module124 a is removably coupled to the base 402, the termination screws 406are communicatively coupled to one or more of the contacts 404 to enablecommunicating information between the termination module 124 a and thefield device 112 a. In other example implementations, the base 402 maybe provided with any other suitable type of field device interface(e.g., a socket) instead of the termination screws 406. In addition,although one field device interface (e.g., the termination screws 406)is shown, the base 402 may be provided with more field device interfacesconfigured to enable communicatively coupling a plurality of fielddevices to the termination module 124 a.

To communicatively couple the termination module 124 a to the universalI/O bus 208 of FIG. 2, the base 402 is provided with a universal I/O busconnector 408 (FIG. 5). When a user plugs the base 402 into the socketrail 202 a or the socket rail 202 b (FIG. 2), the universal I/O busconnector 408 engages the universal I/O bus 208. The universal I/O busconnector 408 may be implemented using any suitable interface includinga relatively simple interface such as, for example, an insulationpiercing connector. To enable communicating information between thetermination module 124 a and the I/O bus 208, the I/O bus connector 408is connected to one or more of the contacts 404 of the terminationmodule 124 a.

As shown in FIG. 5, the base 402 may also be provided with an optionaldisplay interface connector 410 to communicatively couple thetermination module 124 a to an external display (e.g., one of thedisplays 310 of FIG. 3). For example, if the termination module 124 a isimplemented without the display 212, the termination module 124 a canuse the display interface connector 410 to output field deviceidentification information or any other field device information to anexternal display (e.g., one of the displays 310 of FIG. 3).

FIG. 6 is a detailed block diagram of the example termination module 124a of FIGS. 1A and 2, FIG. 7 is a detailed block diagram of the exampleI/O card 132 a of FIG. 1A, and FIG. 8 is a detailed block diagram of theexample labeler 214 of FIGS. 2, 3, and 6. The example termination module124 a, the example I/O card 132 a and the example labeler 214 may beimplemented using any desired combination of hardware, firmware, and/orsoftware. For example, one or more integrated circuits, discretesemiconductor components, or passive electronic components may be used.Additionally or alternatively, some or all of the blocks of the exampletermination module 124 a, the example I/O card 132 a and the examplelabeler 214, or parts thereof, may be implemented using instructions,code, and/or other software and/or firmware, etc. stored on a machineaccessible medium that, when executed by, for example, a processorsystem (e.g., the example processor system 1310 of FIG. 13), perform theoperations represented in the flowcharts of FIGS. 10A, 10B, 11A, 11B,and 12. Although the example termination module 124 a, the example I/Ocard 132 a and the example labeler 214 are described as having one ofeach block described below, each of the example termination module 124a, the example I/O card 132 a and the example labeler 214 may beprovided with two or more of any respective block described below.

Turning to FIG. 6, the example termination module 124 a includes auniversal I/O bus interface 602 to enable the example termination module124 a to communicate with the I/O cards 132 a-b of FIG. 1A (or with anyother I/O cards). The I/O bus interface 602 may be implemented using,for example, the RS-485 serial communication standard, Ethernet, etc. Toidentify an address of the termination module 124 a and/or an address ofthe I/O card 132 a, the termination module 124 a is provided with anaddress identifier 604. The address identifier 604 may be configured toquery the I/O card 132 a (FIG. 1A) for a termination module address(e.g., a network address) when the termination module 124 a is pluggedinto the marshalling cabinet 122. In this manner, the termination module124 a can use the termination module address as a source address whencommunicating information to the I/O card 132 a and the I/O card 132 auses the termination module address as a destination address whencommunicating information to the termination module 124 a.

To control the various operations of the termination module 124 a, thetermination module 124 a is provided with an operation controller 606.In an example implementation, the operation controller can beimplemented using a microprocessor or a microcontroller. The operationcontroller 606 communicates instructions or commands to other portionsof the example termination module 124 a to control the operations ofthose portions.

The example termination module 124 a is provided with an I/O buscommunication processor 608 to exchange information with the I/O card132 a via the universal I/O bus 136 a. In the illustrated example, theI/O bus communication processor 608 packetizes information fortransmission to the I/O card 132 a and depacketizes information receivedfrom the I/O card 132 a. In the illustrated example, the I/O buscommunication processor 608 generates header information for each packetto be transmitted and reads header information from received packets.Example header information includes a destination address (e.g., thenetwork address of the I/O card 132 a), a source address (e.g., thenetwork address of the termination module 124 a), a packet type or datatype (e.g., analog field device information, field device information,command information, temperature information, real-time data values,etc.), and error checking information (e.g., cyclical-redundancy-check(CRC)). In some example implementations, the I/O bus communicationprocessor 608 and the operation controller 606 may be implemented usingthe same microprocessor or microcontroller.

To provide (e.g., obtain and/or generate) field device identificationinformation and/or any other field device information (e.g., activityinformation, data type information, status information, etc.), thetermination module 124 a is provided with the labeler 214 (FIGS. 2 and3). The labeler 214 is described in detail below in connection with FIG.8. The termination module 124 a also includes the display 212 (FIG. 2)to display the field device identification information and/or any otherfield device information provided by the labeler 214.

To control the amount of power provided to the field device 112 a ofFIG. 1A (or any other field device), the termination module 124 a isprovided with a field power controller 610. In the illustrated example,the power supply 216 in the marshalling cabinet 122 (FIG. 2) provideselectrical power to the termination module 124 a to power acommunication channel interface to communicate with the field device 112a. For example, some field devices communicate using 12 volts and otherscommunicate using 24 volts. In the illustrated example, the field powercontroller 610 is configured to condition, regulate, and step up and/orstep down the electrical power provided to the termination module 124 aby the power supply 216. In some example implementations, the fieldpower controller 610 is configured to limit the amount of electricalpower used to communicate with the field devices and/or delivered to thefield devices to substantially reduce or eliminate the risk of sparkingin flammable or combustible environments.

To convert electrical power received from the power supply 216 (FIG. 2)to electrical power for the termination module 124 a and/or the fielddevice 112 a, the termination module 124 a is provided with a powerconverter 612. In the illustrated example, the circuitry used toimplement the termination module 124 a uses one or more voltage levels(e.g., 3.3 V) that are different from the voltage levels required by thefield device 112 a. The power converter 612 is configured to provide thedifferent voltage levels for the termination module 124 a and the fielddevice 112 a using the power received from the power supply 216. In theillustrated example, the electrical power outputs generated by the powerconverter 612 are used to power up the termination module 124 a and thefield device 112 a and to communicate information between thetermination module 124 a and the field device 112 a. Some field devicecommunication protocols require relatively higher or lower voltagelevels and/or electrical current levels than other communicationprotocols. In the illustrated example, the field power controller 610controls the power converter 612 to provide the voltage level(s) topower up the field device 112 a and to communicate with the field device112 a. However, in other example implementations, the electrical poweroutputs generated by the power converter 612 may be used to power up thetermination module 124 a while a separate power supply external to themarshalling cabinet 122 is used to power up the field device 112 a.

To electrically isolate the circuitry of the termination module 124 afrom the I/O card 132 a, the termination module 124 a is provided withone or more isolation devices 614. The isolation devices 614 may beimplemented using galvanic isolators and/or optical isolators. Anexample isolation configuration is described in detail below inconnection with FIG. 9.

To convert between analog and digital signals, the termination module124 a is provided with a digital-to-analog converter 616 and ananalog-to-digital converter 618. The digital-to-analog converter 616 isconfigured to convert digitally represented analog values received fromthe I/O card 132 a to analog values that can be communicated to thefield device 112 a of FIG. 1A. The analog-to-digital converter 618 isconfigured to convert analog values (e.g., measurement values) receivedfrom the field device 112 a to digitally represented values that can becommunicated to the I/O card 132 a. In an alternative exampleimplementation in which the termination module 124 a is configured tocommunicate digitally with the field device 112 a, the digital-to-analogconverter 616 and the analog-to-digital converter 618 can be omittedfrom the termination module 124 a.

To control communications with the field device 112 a, the terminationmodule 124 a is provided with a field device communication processor620. The field device communication processor 620 ensures thatinformation received from the I/O card 132 a is in the correct formatand voltage type (e.g., analog or digital) to be communicated to thefield device 112 a. The field device communication processor 620 is alsoconfigured to packetize or depacketize information if the field device112 a is configured to communicate using digital information. Inaddition, the field device communication processor 620 is configured toextract information received from the field device 112 a and communicatethe information to the analog-to-digital converter 618 and/or to the I/Obus communication processor 608 for subsequent communication to the I/Ocard 132 a. In the illustrated example, the field device communicationprocessor 620 is also configured to timestamp information received fromthe field device 112 a. Generating timestamps at the termination module124 a facilitates implementing sequence of events (SOE) operations usingtimestamp accuracies in the sub-millisecond range. For example, thetimestamps and respective information can be communicated to thecontroller 104 and/or the workstation 102. Sequence of events operationsperformed by, for example, the workstation 102 (FIG. 1A) (or any otherprocessor system) can then be used to analyze what happened before,during, and/or after a particular state of operation (e.g., a failuremode) to determine what caused the particular state of operation tooccur. Timestamping in the sub-millisecond range enables capturingevents using relatively higher granularity. In some exampleimplementations, the field device communication processor and theoperation controller 606 can be implemented using the samemicroprocessor or microcontroller.

In general, field device communication controllers similar to the fielddevice communication controller 620 are provided with communicationprotocol functions or other communication functions (e.g., Fieldbuscommunication protocol functions, HART communication protocol functions,etc.) corresponding to the type of field device with which they areconfigured to communicate. For example, if the field device 112 a isimplemented using a HART device, the field device communicationcontroller 620 of the termination module 124 a is provided with HARTcommunication protocol functions. When the termination module 124 areceives information from the I/O card 132 a intended for the fielddevice 112 a, the field device communication controller 620 formats theinformation in accordance with the HART communication protocol anddelivers the information to the field device 112 a.

In the illustrated example, the field device communication controller620 is configured to process pass-through messages. Pass-throughmessages originate at a workstation (e.g., the workstation 102 of FIG.1A) and are communicated as payload (e.g., the data portion of acommunication packet) through a controller (e.g., the controller 104 ofFIG. 1A) and to a termination module (e.g., the termination module 124 aof FIG. 1A) for delivery to a field device (e.g., the field device 112a). For example, a message originating at the workstation 102 andintended to be delivered to the field device 112 a is tagged at theworkstation 102 with a communication protocol descriptor (e.g., a HARTprotocol descriptor) and/or is formatted in accordance with acommunication protocol of the field device 112 a. The workstation 102then wraps the message into a payload(s) of one or more communicationpackets to deliver the message from the workstation 102, through the I/Ocontroller 104, and to the termination module 124 a as a pass-throughmessage. Wrapping the message involves, for example, packetizing themessage within header information in accordance with a communicationprotocol (e.g., a Fieldbus protocol, a HART protocol, etc.) used tocommunicate with the field devices. When the termination module 124 areceives the communication packet(s) containing the pass-through messagefrom the I/O card 132, the I/O bus communication processor 608 (FIG. 6)extracts the payload(s) from the received communication packet(s). Thefield device communication controller 620 (FIG. 6) then unwraps thepass-through message from the payload(s), formats the message inaccordance with the communication protocol descriptor generated by theworkstation 102 (if not already formatted at the workstation 102), andcommunicates the message to the field device 112 a.

The field device communication controller 620 is also configured tocommunicate pass-through messages to the workstation 102 in a similarmanner. For example, if the field device 112 a generates a message(e.g., a response to the workstation message or any other message)intended to be delivered to the workstation 102, the field devicecommunication controller 620 wraps the message from the field device 112a into the payload of one or more communication packets and the I/O buscommunication processor 608 communicates the one or more packetscontaining the wrapped message to the I/O card 132 a. When theworkstation 102 receives the packets from the controller 104 containingthe wrapped message, the workstation 102 can unwrap and process themessage.

The termination module 124 a is provided with a field device interface622 configured to communicatively couple the termination module 124 a toa field device (e.g., the field device 112 a of FIG. 1A). For example,the field device interface 622 may be communicatively coupled to thetermination screws 406 of FIGS. 4 and 5 via one or more of the contacts404 (FIG. 4).

Turning now to FIG. 7, the example I/O card 132 a of FIG. 1A includes acommunication interface 702 to communicatively couple the I/O card 132 ato the controller 104 (FIG. 1A). In addition, the example I/O card 132 aincludes a communication processor 704 to control communications withthe controller 104 and to pack and unpack information exchanged with thecontroller 104. In the illustrated example, the communication interface702 and the communication processor 704 are configured to communicate tothe controller 104 information intended to be delivered to thecontroller 104 and information to be delivered to the workstation 102(FIG. 1A). To communicate information intended to be delivered to theworkstation 102, the communication interface 702 may be configured towrap the information (e.g., information from the field devices 112 a-c,the termination modules 124 a-c, and/or the I/O card 132 a) in thepayload of one or more communication packet(s) in accordance with acommunication protocol (e.g., a transmission control protocol (TCP), auser datagram protocol (UDP), etc.) and to communicate the packetscontaining the information to the workstation 102. The workstation 102can then unpack the payload(s) from the received packet(s) and unwrapthe information in the payload(s). In the illustrated example, theinformation in the payload of packets communicated by the communicationinterface 702 to the workstation 102 may contain one or more wrappers.For example, information originating at a field device (e.g., the fielddevice 112 a) may be wrapped in a field device communication protocolwrapper (e.g., a FOUNDATION Fieldbus communication protocol wrapper, aHART communication protocol wrapper, etc.), which the communicationinterface 702 wraps in accordance with a TCP-based protocol, a UDP-basedprotocol, or any other protocol to enable the controller 104 tosubsequently communicate the information to the workstation 102. In asimilar manner, the communication interface 702 may be configured tounwrap information communicated by the workstation 102 to the controller104 and intended for delivery to the field devices 112 a-c, thetermination modules 124 a-c, and/or the I/O card 132 a.

In an alternative example implementation, the communication interface702 and the communication processor 704 can communicate information(with or without a field device communication protocol wrapper) to thecontroller 104 and the controller 104 can packetize information intendedto be delivered to the workstation 102 in the same manner as describedabove. The communication interface 702 and the communication processor704 may be implemented using any wired or wireless communicationstandard.

In an alternative example implementation such as, for example, theillustrated example of FIG. 1C, the communication interface 702 and thecommunication processor 704 may be configured to communicate with theworkstation 102 and/or the controller 162 via the LAN 106.

To enable users to interact with and/or access the I/O card 132 a, theI/O card 132 a is provided with one or more user interface ports 706. Inthe illustrated example, the user interface ports 706 include a keyboardinterface port 703 and a portable handheld computer (e.g., a personaldigital assistant (PDA), a tablet PC, etc.) interface port 707. Forexample, a PDA 708 is shown communicatively coupled to the userinterface port 706 using wireless communications.

To communicatively couple the I/O card 132 a to the universal I/O bus136 a (FIG. 1A), the I/O card 132 a is provided with an I/O businterface 710. To process communication information exchanged via theI/O bus 136 a and to control communications made via the I/O bus 136 a,the I/O card 132 a is provided with an I/O bus communication processor712. The I/O bus interface 710 may be similar or identical to the I/Obus interface 602 of FIG. 6 and the I/O bus communication processor 712may be similar or identical to the I/O bus communication processor 608of FIG. 6. To convert electrical power provided by the controller 104 ofFIG. 1A to electrical power needed to power and operate the I/O card 132a and/or to communicate with the termination modules 124 a-c, the I/Ocard 132 a is provided with a power converter 714.

Turning now to FIG. 8, the example labeler 214 includes a communicationinterface 802 configured to communicatively couple the labeler 214 to atermination module (e.g., the termination module 124 a of FIGS. 1A, 2,4, 5, and 6) and/or a field device (e.g., the field device 112 a of FIG.1A) to retrieve field device identification information (e.g., a devicetag value, a device name, an electronic serial number, etc.) and/orother field device information (e.g., activity information, data typeinformation, status information, etc.). To control communications withthe termination module 124 a and/or the field device 112 a, the labeler214 is provided with a communication processor 804.

To detect a connection to a field device (e.g., the field device 112 aof FIG. 1A), the labeler 214 is provided with a connection detector 806.The connection detector 806 may be implemented using, for example, avoltage sensor, a current sensor, a logic circuit, etc. that senses whenthe field device 112 a has been connected to the termination module 124a. In the illustrated example, when the connection detector 806determines that the field device 112 a has been connected to thetermination module 124 a, the connection detector 806 causes anotification (e.g., an interrupt) to be communicated to thecommunication processor 804 indicating the detected connection. Thecommunication processor 804 then queries the termination module 124 aand/or the field device 112 a for the field device identificationinformation of the field device 112 a. In an example implementation, theconnection detector 802 can also be configured to determine the type ofconnection that communicatively couples the field device 112 a to thetermination module 124 a such as, for example, a multi-drop connection,a point-to-point connection, a wireless mesh network connection, anoptical connection, etc.

To display the field device identification information and/or otherfield device information, the labeler 214 is provided with a displayinterface 808. In the illustrated example, the display interface 808 isconfigured to drive and control a liquid crystal display (LCD). Forexample, the display interface 808 may be configured to control the LCDdisplay 212 (FIG. 2) mounted on the termination module 124 a or the LCDdisplay 310 mounted on the marshalling cabinet 300 (FIG. 3). However, inother example implementations, the display interface 808 may instead beconfigured to drive other display types.

To detect the activity of the field device 112 a, the labeler 214 isprovided with a field device activity detector 810. In the illustratedexample, when the communication processor 804 receives data from thetermination module 124 a and/or the field device 112 a, thecommunication processor 804 communicates the received data to the fielddevice activity detector 810. The field device activity detector 810then extracts process variable (PV) values from the data including, forexample, measurement information (e.g., temperature, pressure, linevoltages, etc.) or other monitoring information (e.g., valve closed,valve open, etc.) generated by the field device 112 a. The displayinterface 808 can then display the field device activity information(e.g., the PV values, measurement information, monitoring information,etc.).

To detect the status of the field device 112 a, the labeler 214 isprovided with a field device status detector 812. The field devicestatus detector 812 is configured to extract status information (e.g.,device on, device off, device error, device alarm, device health (openloop, short, etc.), device communication status, etc.) associated withthe field device 112 a from data received by the communication processor804 from the termination module 124 a and/or the field device 112 a. Thedisplay interface 808 can then display the received status information.

To identify the field device 112 a, the labeler 214 is provided with afield device identifier 814. The field device identifier 814 isconfigured to extract the field device identification information (e.g.,a device tag value, a device name, an electronic serial number, etc.)from data received by the communication processor from the terminationmodule 124 a and/or the field device 112 a. The display interface 808can then display the field device identification information. In anexample implementation, the field device identifier 814 may also beconfigured to detect the field device type (e.g., valve actuator,pressure sensor, temperature sensor, flow sensor, etc.).

To identify a data type (e.g., analog or digital) associated with thefield device 112 a, the labeler 214 is provided with a data typeidentifier 816. The data type identifier 816 is configured to extractthe data type identification information from data received by thecommunication processor from the termination module 124 a and/or thefield device 112 a. For example, the termination module 124 a may storea data type descriptor variable that indicates the type of field device(e.g., analog, digital, etc.) with which it is configured tocommunicate, and the termination module 124 a may communicate the datatype descriptor variable to the communication processor 804 of thelabeler 214. The display interface 808 can then display the data type.

FIG. 9 depicts an isolation circuit configuration that may beimplemented in connection with the example termination modules 124 a and124 b of FIG. 1A to electrically isolate the termination modules 124 a-bfrom one another and the field devices 112 a-b from the universal I/Obus 136 a. In the illustrated example, each of the termination modules124 a-b includes respective termination module circuitry 902 and 904(e.g., one or more of the blocks described above in connection with FIG.6). In addition, the termination modules 124 a-b are connected to theirrespective field devices 112 a-b via the field junction box 120 a. Also,the termination modules 124 a-b are connected to the universal I/O bus136 a and the power supply 216. To electrically isolate the terminationmodule circuitry 902 from the universal I/O bus 136 a, the terminationmodule 124 a is provided with an isolation circuit 906. In this manner,the termination module circuitry 902 can be configured to follow (e.g.,float) the voltage level of the field device 112 a if power surges orother power variations occur in the field device 112 a without affectingthe voltage of the universal I/O bus 136 a and without causing damage tothe I/O card 132 a (FIG. 1A). The termination module 124 b also includesan isolation circuit 908 configured to isolate the termination modulecircuitry 904 from the universal I/O bus 136 a. The isolation circuits906 and 908 and any other isolation circuits implemented in thetermination modules 124 a-b may be implemented using optical isolationcircuits or galvanic isolation circuits.

To isolate the termination module circuitry 902 from the power supply216, the termination module 124 a is provided with an isolation circuit910. Similarly, the termination module 124 b is provided with anisolation circuit 912 to isolate the termination module circuitry 904from the power supply 216. By isolating the termination module circuitry902 and 904 from the power supply 216, any power variation (e.g., powersurges, current spikes, etc.) associated with the field devices 112 a-bwill not harm the power supply 216. Also, any power variations in one ofthe termination modules 124 a-b will not harm or affect the operation ofthe other one of the termination modules 124 a-b.

In known process control systems, isolation circuits are provided inknown marshalling cabinets, thereby reducing the amount of spaceavailable for known termination modules. However, providing theisolation circuits 906, 910, 908, and 912 in the termination modules 124a and 124 b as shown in the illustrated example of FIG. 9 reduces theamount of space required in the marshalling cabinet 122 (FIGS. 1A and 2)for isolation circuits, thus increasing the amount of space availablefor termination modules (e.g., the termination modules 124 a-c and 126a-c). In addition, implementing isolation circuits (e.g., the isolationcircuits 906, 908, 910, and 912) in termination modules (e.g., thetermination modules 124 a-b) enables selectively using isolationcircuits only with termination modules that require isolation. Forexample, some of the termination modules 124 a-c and 126 a-c of FIG. 1Amay be implemented without isolation circuits.

FIGS. 10A, 10B, 11A, 11B, and 12 are flowcharts of example methods thatmay be used to implement termination modules (e.g., the terminationmodule 124 a of FIGS. 1A, 2, and 4-6), I/O cards (e.g., the I/O card 132a of FIGS. 1A and 7), and labelers (e.g., the labeler 214 of FIGS. 2, 3,and 8). In some example implementations, the example methods of FIGS.10A, 10B, 11A, 11B, and 12 may be implemented using machine readableinstructions comprising a program for execution by a processor (e.g.,the processor 1312 shown in the example processor system 1310 of FIG.13). The program may be embodied in software stored on a tangible mediumsuch as a CD-ROM, a floppy disk, a hard drive, a digital versatile disk(DVD), or a memory associated with the processor 1312 and/or embodied infirmware and/or dedicated hardware in a well-known manner. Further,although the example program is described with reference to theflowcharts illustrated in FIGS. 10A, 10B, 11A, 11B, and 12, persons ofordinary skill in the art will readily appreciate that many othermethods of implementing the example termination module 124 a, theexample I/O card 132 a, and the example labeler 214 described herein mayalternatively be used. For example, the order of execution of the blocksmay be changed, and/or some of the blocks described may be changed,eliminated, or combined.

Turning in detail to FIGS. 10A and 10B, the example method of FIGS. 10Aand 10B is described in connection with the example termination module124 a of FIGS. 1A, 2, and 4-6. However, the example method of FIGS. 10Aand 10B may be used to implement any other termination module. Theflowchart of FIGS. 10A and 10B is used to describe how the exampletermination module 124 a communicates information between the fielddevice 112 a and the I/O card 132 a. Initially, the termination module124 a determines whether it has received communication information(block 1002). For example, the termination module 124 a determines thatit has received communication information if the I/O bus communicationprocessor 608 (FIG. 6) or the field device communication processor 620indicates via, for example, an interrupt or a status register thatcommunication information has been received. If the termination module124 a determines that it has not received communication information(block 1002), control remains at block 1002 until the termination module124 a receives communication information.

If the termination module 124 a receives communication information(block 1002), the termination module 124 a determines whether itreceived the communication information from a field device (e.g., thefield device 112 a of FIG. 1A) (block 1004) based on, for example, aninterrupt or status register of the field device communication processor620 (FIG. 6). If the termination module 124 a determines that it hasreceived communication information from the field device 112 a (block1004), then the field device communication processor 620 extracts thefield device information and the field device identification informationfrom the received communication information associated with the fielddevice 112 a based on a field device communication protocol (block1006). The field device information may include, for example, fielddevice identification information (e.g., device tags, electronic serialnumbers, etc.), field device status information (e.g., communicationstatus, diagnostic health information (open loop, short, etc.)), fielddevice activity information (e.g., process variable (PV) values), fielddevice description information (e.g., field device type or function suchas, for example, valve actuator, temperature sensor, pressure sensor,flow sensor, etc.), field device connection configuration information(e.g., multi-drop bus connection, point-to-point connection, etc.),field device bus or segment identification information (e.g., fielddevice bus or field device segment via which field device iscommunicatively coupled to termination module), and/or field device datatype information (e.g., analog in (AI) data types, analog out (AO) datatypes, discrete in (DI) data types (e.g., digital in data types),discrete out (DO) data types (e.g., digital out data types), etc.). Thefield device communication protocol may be any protocol (e.g., aFieldbus protocol, a HART protocol, an AS-I protocol, a Profibusprotocol, etc.) used by the field device 112 a. In an alternativeexample implementation, at block 1006, the field device communicationprocessor 620 only extracts the field device information from thereceived communication information and the field device identificationinformation identifying the field device 112 a is stored in thetermination module 124 a. For example, when the field device 112 a isinitially connected to the termination module 124 a, the field device112 a can communicate its identification information to the terminationmodule 124 a and the termination module 124 a can store theidentification information.

The field device communication processor 620 then determines whether ananalog-to-digital conversion is needed (block 1008). For example, if thefield device 112 a communicates analog measurement values, the fielddevice communication processor 620 determines that an analog to digitalconversion is needed or required (block 1008). If an analog to digitalconversion is required, the analog-to-digital converter 618 (FIG. 6)performs the conversion on the received information (block 1010).

After the analog-to-digital conversion (block 1010) or if noanalog-to-digital conversion is required (block 1008), the field devicecommunication processor 620 identifies the data type (e.g., analog,digital, temperature measurement, etc.) associated with the receivedfield device information (block 1012) and generates a data typedescriptor corresponding to the received field device information (block1014). For example, the termination module 124 a can store a data typedescriptor that indicates the data type that it will always receive fromthe field device 112 a or the field device 112 a can communicate a datatype to the termination module 124 a that the field device communicationprocessor 620 uses to generate the data type descriptor at block 1010.

The I/O bus communication processor 608 (FIG. 6) determines thedestination address of the I/O card 132 a (block 1016) to which thetermination module 124 a is to communicate the information received fromthe field device 124 a. For example the communication processor 604(FIG. 6) can obtain the destination address of the I/O card 132 a fromthe address identifier 608 (FIG. 6). In addition, the I/O buscommunication processor 608 determines or generates error checking data(block 1020) to communicate to the I/O card 132 a to ensure that thefield device information is received by the I/O card 132 a withouterrors. For example, the I/O bus communication processor 608 cangenerate cyclical error check (CRC) error checking bits.

The I/O bus communication processor 608 then packetizes the field deviceinformation, the field device identification information, the data typedescriptor, the destination address of the I/O card 132 a, the sourceaddress of the termination module 124 a, and the error checking databased on an I/O bus communication protocol (block 1022). The I/O buscommunication protocol may be implemented using, for example, aTPC-based protocol, a UDP-based protocol, etc. The I/O bus communicationprocessor 608 can obtain the source address of the termination module124 a from the address identifier 604 (FIG. 6). The I/O bus interface602 (FIG. 6) then communicates the packetized information via theuniversal I/O bus 136 a (FIGS. 1A and 2) in combination with packetizedinformation generated by and communicated by other termination modules(e.g., the termination modules 124 b and 124 c of FIG. 1A) (block 1024).For example, the I/O bus interface 602 may be provided with anarbitration circuit or device that sniffs or monitors the universal I/Obus 136 a to determine when the universal I/O bus 136 a is available(e.g., is not being used by the termination modules 124 b-c) tocommunicate the information from the termination module 124 a to the I/Ocard 132 a.

If the termination module 124 b determines at block 1004 that thecommunication information detected at block 1002 is not from the fielddevice 112 a (e.g., the communication information is from the I/O card132 a), the I/O bus communication processor 608 (FIG. 6) extracts adestination address from the received communication information (block1026). The I/O bus communication processor 608 then determines if theextracted destination address matches a destination address of thetermination module 124 a (block 1028) obtained from the addressinterface 604. If the destination address does not match the address ofthe termination module 124 a (e.g., the received information was notintended for delivery to the termination module 124 a) (block 1028),control returns to block 1002 (FIG. 10A). Otherwise, if the destinationaddress matches the address of the termination module 124 a (e.g., thereceived information was intended for delivery to the termination module124 a) (block 1028), the I/O bus communication processor 608 extractsthe field device information from the received communication informationbased on the I/O bus communication protocol (block 1030) and verifiesthe integrity of the data (block 1032) using, for example, a CRCverification process based on error detection information in thereceived communication information. Although not shown, if the I/O buscommunication processor 608 determines at block 1032 that an errorexists in the received communication information, the I/O buscommunication processor 608 sends a message to the I/O card 132 arequesting a re-transmit.

After verifying the data integrity (block 1032), the I/O buscommunication processor 608 (or the field device communication processor620) determines whether a digital-to-analog conversion is required(block 1034). For example, if a data type descriptor stored in thetermination module 124 a indicates that the field device 112 a requiresanalog information, then the I/O bus communication processor 608determines that a digital-to-analog conversion is required (block 1034).If a digital-to-analog conversion is required (block 1034), thedigital-to-analog converter 616 (FIG. 6) performs the digital-to-analogconversion on the field device information (block 1036). After thedigital-to-analog conversion is performed (block 1036) or if nodigital-to-analog conversion is required (block 1034), the field devicecommunication processor 620 communicates the field device information tothe field device 112 a via the field device interface 622 (FIG. 6) usingthe field device communication protocol of the field device 112 a (block1038).

After the field device communication processor 620 communicates thefield device information to the field device 112 a or after the I/O buscommunication processor 608 communicates the field device information tothe I/O card 132 a, the process of FIGS. 10A and 10B is ended and/orcontrol is returned to, for example, a calling process or function.

FIGS. 11A and 11B depict a flowchart of an example method that may beused to implement the I/O card 132 a of FIG. 1A to exchange informationbetween termination module 124 a and the controller 104 of FIG. 1A.Initially, the I/O card 132 a determines whether it has receivedcommunication information (block 1102). For example, the I/O card 132 adetermines that it has received communication information if thecommunication processor 704 (FIG. 7) indicates via, for example, aninterrupt or a status register that it has received communicationinformation. If the I/O card 132 a determines that it has not receivedcommunication information (block 1102), control remains at block 1102until the I/O card 132 a receives communication information.

If the I/O card 132 a receives communication information (block 1102),the I/O card 132 a determines whether it received the communicationinformation from the controller 104 (FIG. 1A) (block 1104) based on forexample an interrupt or status register of the communication processor704. If the I/O card 132 a determines that it has received communicationinformation from the controller 104 (block 1104), then the communicationprocessor 704 extracts the termination module information (which mayinclude field device information) from the received communicationinformation associated with the termination module 124 a (block 1106).

The communication processor 704 identifies the data type (e.g., fielddevice analog information, field device digital information, terminationmodule control information to control or configure the terminationmodule, etc.) associated with the received termination moduleinformation (block 1108) and generates a data type descriptorcorresponding to the received termination module information (block1110). In an alternative example implementation, the data typedescriptor is generated at the workstation 102 (FIG. 1A) and thecommunication processor 704 need not generate the data type descriptor.

The I/O bus communication processor 712 (FIG. 7) then determines thedestination address of the termination module 124 a (block 1112). Inaddition, the I/O bus communication processor 712 determines errorchecking data (block 1114) to communicate to the termination module 124a with the termination module information to ensure that the terminationmodule 124 a receives the information without errors. For example, theI/O bus communication processor 712 can generate cyclical error check(CRC) error checking bits.

The I/O bus communication processor 712 then packetizes the terminationmodule information, the data type descriptor, the destination address ofthe termination module 124 a, the source address of the terminationmodule 124 a, and the error checking data based on the I/O buscommunication protocol (block 1116). The I/O bus interface 710 (FIG. 7)then communicates the packetized information via the universal I/O bus136 a (FIGS. 1A and 2) in combination with packetized informationdestined for other termination modules (e.g., the termination modules124 b and 124 c of FIG. 1A) (block 1118). For example, the I/O buscommunication processor 702 may packetize other termination moduleinformation using the destination addresses of, for example, thetermination modules 124 b and 124 c and communicate termination moduleinformation for all of the termination modules 124 a-c via the universalI/O bus 136 a using the RS-485 standard. Each of the termination modules124 a-c can extract its respective information from the universal I/Obus 136 a based on the destination addresses provided by the I/O card132 a.

If the I/O card 132 a determines at block 1104 that the communicationinformation detected at block 1102 is not from the controller 104 (e.g.,the communication information is from the one of the termination modules124 a-c), the I/O bus communication processor 712 (FIG. 7) extracts asource address (e.g., a source address of one of the termination modules124 a-c) from the received communication information (block 1122). TheI/O bus communication processor 712 then extracts a data type descriptor(e.g., digitally encoded analog data type, digital data type,temperature data type, etc.) (block 1124). The I/O bus communicationprocessor 712 also extracts the termination module information (whichmay include field device information) from the received communicationinformation based on the I/O bus communication protocol (block 1126) andverifies the integrity of the data (block 1128) using, for example, aCRC verification process based on error detection information in thereceived communication information. Although not shown, if the I/O buscommunication processor 712 determines at block 1128 that an errorexists in the received communication information, the I/O buscommunication processor 712 sends a re-transmit request message to thetermination module associated with the source address obtained at block1122.

After verifying the data integrity (block 1128), the communicationprocessor 704 packetizes the termination module information (using thesource address of the termination module and the data type descriptor)and the communication interface 702 communicates the packetizedinformation to the controller 104 (block 1130). If the information isintended to be delivered to the workstation 102, the controller 104 cansubsequently communicate the information to the workstation 102. Afterthe communication interface 702 communicates the information to thecontroller 104 or after the I/O bus interface 710 communicates thetermination module information to the termination module 124 a, theprocess of FIGS. 11A and 11B is ended and/or control is returned to, forexample, a calling process or function.

FIG. 12 is a flowchart of an example method that may be used toimplement the labeler 214 of FIGS. 2, 3, and 8 to retrieve and displayinformation associated with field devices (e.g., the field device 112 aof FIG. 1A) communicatively coupled to termination modules (e.g., thetermination module 124 a of FIGS. 1, 2, and 4-6). Initially, theconnection detector 806 (FIG. 8) determines whether a field device(e.g., the field device 112 a) is connected to the termination module124 a (e.g., connected to the termination screws 406 of FIGS. 4 and 5and/or the field device interface 622 of FIG. 6) (block 1202). If theconnection detector 806 determines that the field device 112 a (or anyother field device) is not connected to the termination module 124 a(block 1202) control remains at block 1202 until the connection detector806 determines that the field device 112 a (or any other field device)is connected to the termination module 124 a.

If the connection detector 806 determines that the field device 112 a isconnected to the termination module 124 a (block 1202), the field deviceidentifier 814 obtains field device identification information (e.g., adevice tag value, a device name, an electronic serial number, etc.) thatidentifies the field device 112 a (block 1204). For example, the fielddevice identifier 814 can send the field device 112 a a query requestingthe field device 112 a to transmit its field device identificationinformation. In another example implementation, upon initial connectionto the termination module 124 a, the field device 112 a canautomatically communicate its field device identification information tothe field device identifier 814.

The field device identifier 814 then determines if the field device 112a is assigned to communicate via the universal I/O bus 136 a with theI/O card 132 a (block 1206) based on the field device identificationinformation. For example, the field device identifier 814 cancommunicate the field device identification information to the I/O card132 a via the termination module 124 a and the I/O card 132 a cancompare the field device identification information with field deviceidentification numbers stored in the data structure 133 (FIG. 1A) or ina similar data structure stored in the workstation 102. The datastructure 133 can be populated by engineers, operators, or users withfield device identification numbers of field devices (e.g., the fielddevices 112 a-c) that are to communicate with the I/O card 132 a via theuniversal I/O bus 136 a. If the I/O card 132 a determines that the fielddevice 112 a is assigned to the I/O bus 136 a and/or the I/O card 132 a,the I/O card 132 a communicates a confirmation message to the fielddevice identifier 814.

If the field device identifier 814 determines that the field device 112a is not assigned to communicate via the I/O bus 136 a (block 1206), thedisplay interface 808 (FIG. 8) displays an error message (block 1208).Otherwise, the display interface 808 displays the field deviceidentification information (block 1210). In the illustrated example, thefield device status detector 812 detects the field device status (e.g.,device on, device off, device error, etc.) and the display interface 808displays the status information (block 1212). In addition, the fielddevice activity detector 810 (FIG. 8) detects the activity of the fielddevice 112 a (e.g., measurement and/or monitoring information) and thedisplay interface 808 displays the activity information (block 1214).Also, the data type detector 816 (FIG. 8) detects the data type (e.g.,analog, digital, etc.) of the field device 112 a and the displayinterface 808 displays the data type (block 1216).

After the display interface 808 displays the error message (block 1208)or after the display interface 808 displays the data type (block 1216),the labeler 214 determines whether it should continue monitoring (block1218) based on, for example, whether the termination module 124 a hasbeen turned off or unplugged from the marshalling cabinet 122 (FIGS. 1Aand 2). If the labeler 214 determines that it should continuemonitoring, control is passed back to block 1202. Otherwise, the exampleprocess of FIG. 12 is ended and/or control is returned to a callingfunction or process.

FIG. 13 is a block diagram of an example processor system 1310 that maybe used to implement the apparatus and methods described herein. Forexample, processor systems similar or identical to the example processorsystem 1310 may be used to implement the workstation 102, the controller104, the I/O card 132 a, and/or the termination modules 124 a-c and 126a-c of FIG. 1A. Although the example processor system 1310 is describedbelow as including a plurality of peripherals, interfaces, chips,memories, etc., one or more of those elements may be omitted from otherexample processor systems used to implement one or more of theworkstation 102, the controller 104, the I/O card 132 a, and/or thetermination modules 124 a-c and 126 a-c.

As shown in FIG. 13, the processor system 1310 includes a processor 1312that is coupled to an interconnection bus 1314. The processor 1312includes a register set or register space 1316, which is depicted inFIG. 13 as being entirely on-chip, but which could alternatively belocated entirely or partially off-chip and directly coupled to theprocessor 1312 via dedicated electrical connections and/or via theinterconnection bus 1314. The processor 1312 may be any suitableprocessor, processing unit or microprocessor. Although not shown in FIG.13, the system 1310 may be a multi-processor system and, thus, mayinclude one or more additional processors that are identical or similarto the processor 1312 and that are communicatively coupled to theinterconnection bus 1314.

The processor 1312 of FIG. 13 is coupled to a chipset 1318, whichincludes a memory controller 1320 and a peripheral input/output (I/O)controller 1322. As is well known, a chipset typically provides I/O andmemory management functions as well as a plurality of general purposeand/or special purpose registers, timers, etc. that are accessible orused by one or more processors coupled to the chipset 1318. The memorycontroller 1320 performs functions that enable the processor 1312 (orprocessors if there are multiple processors) to access a system memory1324 and a mass storage memory 1325.

The system memory 1324 may include any desired type of volatile and/ornon-volatile memory such as, for example, static random access memory(SRAM), dynamic random access memory (DRAM), flash memory, read-onlymemory (ROM), etc. The mass storage memory 1325 may include any desiredtype of mass storage device. For example, if the example processorsystem 1310 is used to implement the workstation 102 (FIG. 1A), the massstorage memory 1325 may include a hard disk drive, an optical drive, atape storage device, etc. Alternatively, if the example processor system1310 is used to implement the controller 104, one of the I/O cards 132a-b and 134 a-b, or one of the termination modules 124 a-c and 126 a-c,the mass storage memory 1325 may include a solid-state memory (e.g., aflash memory, a RAM memory, etc.), a magnetic memory (e.g., a harddrive), or any other memory suitable for mass storage in the controller104, the I/O cards 132 a-b and 134 a-b, or the termination modules 124a-c and 126 a-c.

The peripheral I/O controller 1322 performs functions that enable theprocessor 1312 to communicate with peripheral input/output (I/O) devices1326 and 1328 and a network interface 1330 via a peripheral I/O bus1332. The I/O devices 1326 and 1328 may be any desired type of I/Odevice such as, for example, a keyboard, a display (e.g., a liquidcrystal display (LCD), a cathode ray tube (CRT) display, etc.), anavigation device (e.g., a mouse, a trackball, a capacitive touch pad, ajoystick, etc.), etc. The network interface 1330 may be, for example, anEthernet device, an asynchronous transfer mode (ATM) device, an 802.11device, a DSL modem, a cable modem, a cellular modem, etc. that enablesthe processor system 1310 to communicate with another processor system.

While the memory controller 1320 and the I/O controller 1322 aredepicted in FIG. 13 as separate functional blocks within the chipset1318, the functions performed by these blocks may be integrated within asingle semiconductor circuit or may be implemented using two or moreseparate integrated circuits.

Although certain methods, apparatus, and articles of manufacture havebeen described herein, the scope of coverage of this patent is notlimited thereto. To the contrary, this patent covers all methods,apparatus, and articles of manufacture fairly falling within the scopeof the appended claims either literally or under the doctrine ofequivalents.

1. An apparatus to communicatively couple field devices to a controllerin a process control system, the apparatus comprising: a first interfaceconfigured to receive first information from a field device using afirst communication protocol; a communication processor communicativelycoupled to the first interface and configured to encode the firstinformation for communication via a bus using a second communicationprotocol; and a second interface communicatively coupled to thecommunication processor and the bus and configured to communicate thefirst information via the bus using the second communication protocol,wherein the bus is configured to use the second communication protocolto communicate second information associated with another field device.2. An apparatus as defined in claim 1, wherein the bus is configured tocommunicate the first and second information via the same communicationmedium.
 3. An apparatus as defined in claim 1, wherein the secondcommunication protocol is a packet-based communication protocol.
 4. Anapparatus as defined in claim 1, wherein the bus includes an electricalconductor.
 5. An apparatus as defined in claim 1, further comprising anaddress identifier configured to determine a source address of theapparatus, wherein the communication processor communicates the sourceaddress of the apparatus in association with the first information. 6.An apparatus as defined in claim 1, further comprising a data typedetector configured to identify a data type associated with the firstinformation.
 7. An apparatus as defined in claim 1, wherein thecommunication processor is configured to generate header informationidentifying the first information and communicate the header informationin association with the first information.
 8. An apparatus as defined inclaim 7, wherein the header information includes identificationinformation indicative of the field device.
 9. An apparatus as definedin claim 1, wherein the communication processor is configured to decodethird information received via the bus using the second communicationprotocol, and wherein the first interface is configured to communicatethe third information to the field device using the first communicationprotocol.
 10. A machine accessible medium having instructions storedthereon that, when executed, cause a machine to: receive firstinformation from a field device using a first communication protocol;encode the first information for communication using a secondcommunication protocol configured to communicate second informationassociated with another field device; and communicate the firstinformation via a bus using the second communication protocol.
 11. Amachine accessible medium as defined in claim 10 having instructionsstored thereon that, when executed, cause the machine to communicate thefirst information via the bus to a controller configured to receiveinformation from the another field device via the bus.
 12. A machineaccessible medium as defined in claim 10 having instructions storedthereon that, when executed, cause the machine to communicate the firstinformation via the bus using a packet-based protocol.
 13. A machineaccessible medium as defined in claim 10 having instructions storedthereon that, when executed, cause the machine to determine at least oneof field device identification information indicative of the fielddevice or a status of the field device in response to receiving thefirst information from the field device.
 14. A machine accessible mediumas defined in claim 10 having instructions stored thereon that, whenexecuted, cause the machine to: identify a data type associated with thefirst information; generate a data type descriptor corresponding to thedata type; and communicate the data type descriptor via the bus inassociation with the first information.
 15. A machine accessible mediumas defined in claim 10 having instructions stored thereon that, whenexecuted, cause the machine to: receive third information via the bususing the second communication protocol; and communicate the thirdinformation to the field device using the first communication protocol.16. A machine accessible medium as defined in claim 15 havinginstructions stored thereon that, when executed, cause the machine to:identify a data type descriptor associated with the third information;and communicate the third information to the field device using thefirst communication protocol based on the data type descriptor.
 17. Amachine accessible medium as defined in claim 10, wherein the bus isconfigured to communicate the second information to the controller usingthe second communication protocol.
 18. A machine accessible medium asdefined in claim 10 having instructions stored thereon that, whenexecuted, cause the machine to generate timestamp information associatedwith the first information and to communicate the timestamp informationin association with the first information via a bus using the secondcommunication protocol.
 19. A machine accessible medium as defined inclaim 18, wherein the timestamp information includes sub-millisecondrange timestamps.
 20. A method to communicate information between acontroller and field devices in a process control system, the methodcomprising: receiving first information from a field device using afirst communication protocol; encoding the first information forcommunication using a second communication protocol configured tocommunicate second information associated with another field device; andcommunicating the first information to a controller via a bus using thesecond communication protocol.
 21. A method as defined in claim 20,wherein the second communication protocol includes a packet-basedprotocol.
 22. A method as defined in claim 20, further comprisingautomatically associating at least one of field device identificationinformation or status information with the field device in response toreceiving communication information from the field device.
 23. A methodas defined in claim 20, further comprising: identifying a data typeassociated with the first information; generating a data type descriptorindicative of the data type; and communicating the data type descriptorvia the bus in association with the first information.
 24. A method asdefined in claim 20, further comprising: receiving third information viathe bus using the second communication protocol; and communicating thethird information to the field device using the first communicationprotocol.
 25. A method as defined in claim 24, further comprising:identifying a data type descriptor associated with the thirdinformation; and communicating the third information to the field deviceusing the first communication protocol based on the data typedescriptor.
 26. A method as defined in claim 20, wherein the bus isconfigured to communicate the second information to the controller usingthe second communication protocol.
 27. An apparatus to communicativelycouple field devices to a controller in a process control system, theapparatus comprising: a plurality of sockets configured to receive aplurality of termination modules, wherein each of the terminationmodules is configured to be communicatively coupled to at least onefield device in a process control system; and a communication businterface communicatively coupled to each of the plurality of socketsand configured to communicate first field device information associatedwith one of the termination modules and second field device informationassociated with a second one of the termination modules.
 28. Anapparatus as defined in claim 27, wherein the first field deviceinformation is associated with a first field device communicativelycoupled to the first one of the termination modules, and wherein thesecond field device information is associated with a second field devicecommunicatively coupled to the second one of the termination modules.29. An apparatus as defined in claim 27, further comprising at least onedisplay configured to display field device identification informationassociated with at least one of the termination modules.
 30. Anapparatus as defined in claim 29, wherein the communication businterface is configured to use a wireless communication protocol.
 31. Anapparatus as defined in claim 29, wherein the communication businterface is configured to use an RS-485 serial communication standard.32. An apparatus to display information associated with a field devicein a process control system, the apparatus comprising: a connectiondetector configured to detect a connection to a field device; a fielddevice identifier configured to determine field device identificationinformation indicative of the identity of the field device; and adisplay interface configured to display the field device identificationinformation.
 33. An apparatus as defined in claim 32, wherein the fielddevice identifier is configured to automatically determine the fielddevice identification information indicative of the identity of thefield device in response to the connection detector detecting theconnection to the field device.
 34. An apparatus as defined in claim 32,wherein the connection detector is further configured to detect the typeof connection to the field device, wherein the type of connection is atleast one of a multi-drop connection, a point-to-point connection, awireless connection, or an optical connection.
 35. An apparatus asdefined in claim 32, further comprising a signal activity detectorconfigured to detect a voltage level provided by the field device via acommunication medium.
 36. An apparatus as defined in claim 32, furthercomprising a field device status detector configured to detect a statusof the field device, wherein the display interface is configured todisplay the status.
 37. An apparatus as defined in claim 32, wherein thestatus information includes at least one of a health status of the fielddevice or a process variable value associated with an operation of thefield device.
 38. An apparatus to isolate electrical circuitryassociated with a termination module communicatively coupled to a fielddevice in a process control system, the apparatus comprising: a firstisolation circuit communicatively coupled to termination modulecircuitry and configured to be communicatively coupled to a bus, whereinthe termination module circuitry is configured to communicate with afield device, and wherein the bus enables the termination module tocommunicate with a controller; and a second isolation circuitcommunicatively coupled to the termination module circuitry andconfigured to be communicatively coupled to a power supply that provideselectrical power to the termination module circuitry.
 39. An apparatusas defined in claim 38, wherein the first isolation circuit isimplemented using one of a galvanized isolation circuit or an opticalisolation circuit.
 40. An apparatus as defined in claim 38, wherein thefirst isolation circuit enables the termination module circuitry tofollow a voltage level of the field device without affecting a voltageof the bus.
 41. An apparatus as defined in claim 38, wherein the secondisolation circuit enables the termination module circuitry to follow avoltage level of the field device without affecting the operation of thepower supply.